汽轮机冷态启动温升率与转子材料硬度值的关系

摘要

Long time operation of steam turbine rotors under high temperature and high pressure conditions causes the drop of material hardness value, which in its turn affects the material mechanical properties of creep and fatigue and the rotor life expenditure.The temperature field, thermal stress field and hardness value of 300 MW steam turbine were calculated and analyzed by using ALGOR software, the relationships between temperature rise rate and thermal stress, and the effect of temperature rise rate on the fatigue life of rotor were studied,the varying law of hardness value with time was discussed, and with the decline of hardness values, equal life expenditure ratio can be achieved by reducing the temperature rise rate during unit cold start each time.The prediction precision of residual life for defected stream turbine rotor is improved, which provided a basis for safe and reliable operation of the old unit.%汽轮机转子长期在高温、高压状态下运行,会发生材料硬度值下降的现象.硬度的变化影响着材料的疲劳及蠕变力学性能,进而影响着转子寿命损耗.利用ALCOR对300MW汽轮机转子温度场、热应力场及硬度值进行了计算和分析,研究了温升率与热应力的关系以及温升率对转子疲劳寿命的影响,探讨了材料硬度值随时间变化的规律.发现随硬度值下降,可通过降低温升率来实现每次机组冷态启动寿命损耗率相等.提高了转子剩余寿命预测精度,为老机组安全可靠运行提供了依据.